The combining of multiple forms of media in the communication of data and information is commonly referred to in the art as multi-media. Multi-media allows communication through integrated forms of media such as audio, video, text, graphics, fax, and telephony, thereby providing a very powerful form of communication. By combining several forms of media, more effective communication can be accomplish when compared with a single media format such as text-based communication.
Many multi-media communication formats exist, however, such formats generally include voice communications, audio processing, data communications, image processing, and telecommunications using various networks such as Integrated Services Digital Network (ISDN).
Telecommunications via ISDN is a new concept in phone networking that has been designed to overcome the present public switched phone network's limitations. The public switched phone network in use today employs voice lines with very narrow bandwidths which limit the speed of data transmission, uses inefficient and expensive separate voice and data networks, has no standard out-of-band signaling system, and other problems. ISDN standardizes voice, data, and signaling, makes all transmission circuits end-to-end digital, adopts a standard out-of-band signaling system, and brings significantly more bandwidth to the desktop. This enables ISDN to provide substantial increases in the speed of dialing, desktop video conferencing, e-mail, collaborative computing, internet access at 128 Kbps, shared screen, and other services.
Devices which combine a couple of the aforementioned media communication formats, such as a computer and a telephone, into a single communication device have been developed. For example, in U.S. Pat. No. 5,189,632 entitled PORTABLE PERSONAL COMPUTER AND MOBILE TELEPHONE DEVICE issued to Paajanen et al. on Feb. 23, 1993, there is disclosed a handheld communication device which combines a computer with a telephone. The device has a folding double-sided keyboard with a set of buttons for operating the device as a telephone on one side and a second set of buttons on the opposite side for operating the device as a computer. The keyboard is hinged to the main housing of the device in such a manner that when the keyboard is unfolded from the main housing, a computer display screen is uncovered and the buttons for operating the device as a computer are accessible. When the keyboard is folded up against the main housing of the device, the keyboard partially covers the display screen and only the buttons for operating the device as a telephone are accessible.
In U.S. Pat. No. 5,276,916 entitled COMMUNICATION DEVICE HAVING A SPEAKER AND MICROPHONE issued to Pawlish et al. on Jan. 4, 1994, there is disclosed a handheld communication device which combines a radio with speaker-microphone in a folding housing assembly. One of the housing portions include the radio circuitry, the keypad, and the speaker. The other housing portion includes two microphones. The housing portions fold or unfold between first and second relative positions, with one of the positions providing a handset configuration and the other providing a speaker-microphone configuration. A position sensing switch determines the relative position of the housing portions in order to determine whether the device is in the handset configuration or speaker-microphone configuration. After sensing the configuration of the housing, a controller disposed in the device adjusts the gain of an audio amplifier according to the sensed configuration. The use of a position sensing switch in Pawlish et al. simplifies the operation of the device.
Other communication devices have been developed which include features that make the devices more user-friendly. In U.S. Pat. No. 5,436,954 entitled FOLDABLE RADIO TELEPHONE SET WITH ROTARY SELECTOR INTEGRAL WITH FOLDABLE HINGE ELEMENT issued to Nishiyama et al. on Jul. 25, 1995, discloses a portable radio telephone set contained in a folding housing. The telephone set includes a thumb rotatable telephone function selector that forms part of the housing hinge. The single rotatable function selector reduces the number of key buttons required for selecting the multiple telephone functions provided by the phone. U.S. Pat. No. 5,173,686 entitled SLIDING ACCOMMODATION TYPE LIQUID CRYSTAL DISPLAY DEVICE issued to Fujihara on Dec. 22, 1992, discloses a liquid crystal display unit which slides in and out of a housing. When the display unit is drawn out of the housing, it can be rotated to a predetermined viewing angle. The display unit includes a switches which sense the rotational angle of the display to automatically switch on or off the display. U.S. Pat. No. 5,224,151 entitled AUTOMATIC HANDSET-SPEAKERPHONE SWITCHING ARRANGEMENT FOR PORTABLE COMMUNICATION DEVICE issued on Jun. 29, 1993 to Bowen et al. and assigned to AT&T Bell Laboratories, the assignee herein, discloses a handset device which operates in both a handset and speakerphone mode. The device includes means for automatically switching between the two operating modes based on distance between the handset and the user's ear, this distance being determined by an infrared range detection unit built into the handset.
None of the devices described above combine more than two communication media formats into a single communication device and thus, fail to take full advantage of ISDN, Moreover, most of those devices do not have operating formats which can easily is be selected without the need to press or select various buttons and switches.
In response to the need for a user-friendly ISDN multimedia capable device, the assignee herein in the earlier mentioned U.S. patent application Ser. No. 08/616,871, describes an ISDN multimedia capable device that electronically changes functional states without a complex and confusing user interface process. The device described therein has a hinged keyboard cover which includes a multimedia terminal keypad. The keypad described therein can be illuminated for low light operation via a number of well known methods which include the use of a locally side mounted LED and light guide arrangement which operates to direct light to graphics on the outer layer of the keys. The LED and light guide arrangement described above and other like lighting methods require the use of relatively expensive and labor intensive wiring. The expense of such techniques increase significantly when the wiring must be routed through the two sets of hinges such as is the case in the multimedia device described in U.S. patent application Ser. No. 08/616,871. The multimedia device described therein includes two sets of hinges which provide a novel interconnected side hinge and keyboard cover motion that changes the functional state of the multimedia device.
Accordingly, the is a need for an illumination technique that enables low light operation of a keypad, especially a multimedia terminal keypad, which does not require the use of electrically active components that require expensive and labor intensive external electrical connections.